Abstract:
Nanotechnology enabled synthetic biology could one day lead to an artificial construct that operates like a living cell. That day might be a considerable distance off, given the difficulties scientists are still having in even understandiing the organizing principles and workings of a cell, not to mention being able to duplicate cell components and assembling them into a working whole. The large discrepancy between the functional density (i.e., the number of components or interconnection of components per unit volume) of cells and engineered systems highlights the inherent challenges posed by such a task. Just take 'simple' bacteria like Escherichia coli (which has an approx. 2 square micrometer cross-sectional area). The E. coli cell has some 4.6-million base-pair chromosome (the equivalent of a 9.2 megabit memory) that codes for as many as 4,300 different polypeptides under the inducible control of several hundred different promoters (example quoted from Nano-enabled synthetic biology). The most advanced silicon chips will be able in a few years time to come close to this performance (on the other hand, you have several trillion E. coli in your gut; you would need to swallow a lot of computer chips to match this combined 'computing' power). Another way to look at the synthetic cell challenge is to regard the cellular environment as a highly complex synthetic medium, in which numerous multistep reactions take place simultaneously with an efficiency and specificity that scientists are not capable of duplicating at this scale. Researchers in The Netherlands have now succeeded in constructing nanoreactors that can be used to perform one-pot multistep reactions - another step towards the goal of artificial cell-like devices, but more promising in the short term for screening and diagnostic applications.